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Basics : Knowledge Representation in AI

St Germain en Laye, December 2nd 2024.

 

Knowledge Representation (KR) in AI is thriving and evolving rapidly, with significant contributions from both academia and industry in the United States. Key trends and research directions in KR today focus on addressing the complexities of representing, reasoning about, and utilizing knowledge in AI systems. Here are some of the prominent areas of research.

 

Neural-symbolic Integration

This area is at the intersection of symbolic reasoning and neural networks. The goal is to combine the strengths of symbolic AI (logical reasoning, structured representations) with deep learning (learning from data, pattern recognition).

  • Key Challenges: Developing models that can learn from raw data while also enabling symbolic reasoning, such as performing logical deductions, planning, or handling abstract concepts.
  • Recent Work: Research includes work on neural networks that can perform symbolic reasoning tasks (e.g., using differentiable programming), and symbolic tools that enable models to learn from structured data (e.g., knowledge graphs or ontologies).
  • Notable Approaches:
    • Neural-Reasoning Models: For example, combining graph neural networks with symbolic reasoning to improve tasks like commonsense reasoning, language understanding, and even decision-making.
    • End-to-End Symbolic AI: Efforts like Facebook’s work on incorporating structured knowledge into transformers or OpenAI’s work on grounding language models to structured knowledge.

 

Knowledge Graphs and Knowledge Bases

Knowledge graphs (KGs) are a powerful tool for representing knowledge as a network of entities and relationships, often used for question answering, recommendation systems, and semantic search.

  • Key Challenges: Building scalable, accurate, and up-to-date knowledge graphs. Also, dealing with challenges in handling unstructured data, reasoning over incomplete or noisy data, and making KGs more interpretable.
  • Recent Work:
    • Scaling Knowledge Graphs: Research into methods for automatically constructing, updating, and expanding KGs, including work on hybrid models combining rule-based and data-driven methods.
    • Representation Learning on KGs: Leveraging deep learning techniques (e.g., graph neural networks) to embed knowledge graph entities and relationships into vector spaces that allow for more efficient reasoning and querying.

 

Commonsense Reasoning and Cognitive Models

Commonsense reasoning involves representing and reasoning about the everyday knowledge that humans typically take for granted. It’s a challenging aspect of AI that requires models to infer unstated facts based on context.

  • Key Challenges: Encoding knowledge that is often implicit, non-formal, and context-dependent. Ensuring that AI models can reason about events and understand causality.
  • Recent Work:
    • Large Language Models (LLMs) and Commonsense: Studies focus on improving LLMs like GPT or BERT to better understand and reason with commonsense knowledge. For example, OpenAI’s work with GPT-4 has involved adding more robust commonsense reasoning capabilities.
    • Hybrid Models for Reasoning: Researchers are exploring how neural models can be augmented with rule-based systems or explicit representations of commonsense knowledge (e.g., ConceptNet or ATOMIC knowledge graph) to improve the reasoning process.

 

Explainable AI (XAI)

Knowledge representation is crucial for making AI models more interpretable and explainable. Explainable AI seeks to make AI decisions more understandable to humans, which is critical for safety, ethics, and trust.

  • Key Challenges: Ensuring that models are not only accurate but also transparent in their decision-making process, which requires clear representation of knowledge that can be traced and interpreted.
  • Recent Work:
    • Explainable Reasoning: Research into how symbolic knowledge representations can help explain the reasoning behind deep learning models, especially in domains like healthcare, law, and autonomous driving.
    • Interpretable Models with External Knowledge: Methods are being developed that allow models to integrate and reason over structured external knowledge (e.g., knowledge graphs, ontologies) in a way that enhances both performance and interpretability.

Example of XAI at Nexyad, see Autonomous Cars & Autonomous Trucks driven by Prudence

 

Ontologies and Formal Logic Systems

Ontologies are structured frameworks for organizing and representing knowledge, typically through formalized sets of concepts and relationships in a specific domain. Logic systems (e.g., description logics, non-monotonic logics) are used to formalize reasoning.

  • Key Challenges: Handling ambiguous, incomplete, or inconsistent knowledge. Developing scalable systems for reasoning over large, complex ontologies.
  • Recent Work:
    • Scalable Reasoning: Research on developing more efficient and scalable reasoning algorithms for large ontologies, particularly in real-time or big data settings.
    • Adaptive Ontologies: Work on dynamic or self-learning ontologies that evolve over time as new data or concepts emerge.

 

Causal Reasoning and Representation

Understanding cause-and-effect relationships is crucial for reasoning in dynamic environments. Causal reasoning can enhance knowledge representation by enabling AI systems to predict and reason about future events based on current knowledge.

  • Key Challenges: Identifying causal structures from data, reasoning under uncertainty, and integrating causal models with other types of knowledge representations.
  • Recent Work:
    • Causal Inference with Neural Networks: Techniques like causal discovery from data, using deep learning models to learn causal structures, and incorporating causal reasoning into knowledge graphs.
    • Causal Representation Learning: Representing causal knowledge in ways that facilitate inference about interventions or counterfactuals, and making this representation interpretable to humans.

 

Multi-modal Knowledge Representation

Multi-modal knowledge representation involves integrating data from different sources (e.g., text, images, videos, sensors) into a unified framework that allows for reasoning across diverse types of information.

  • Key Challenges: Aligning and integrating information from different modalities, and designing systems that can reason effectively across these different data types.
  • Recent Work:
    • Vision-Language Models: Advancements in multimodal models (like CLIP and DALL-E by OpenAI, or Flamingo by DeepMind) that combine vision and language for better representation and reasoning capabilities.
    • Cross-modal Knowledge Graphs: Research on building knowledge graphs that incorporate information from multiple modalities (e.g., text, image, and sensor data) to improve understanding and reasoning.

 

Human-AI Collaboration and Knowledge Sharing

A growing area of research focuses on how AI systems can better represent and share knowledge with humans, allowing for more effective collaboration between humans and machines.

  • Key Challenges: Ensuring that AI systems can understand and adapt to human knowledge, providing interfaces for interactive knowledge sharing, and designing systems that can support human decision-making.
  • Recent Work:
    • Interactive Knowledge Acquisition: Methods for systems to acquire and update knowledge from human interaction, such as learning from feedback or correcting misconceptions in real time.
    • Collaborative Knowledge Engineering: Research on systems that facilitate the joint construction of knowledge, where both AI and human participants contribute to the knowledge representation process.

 

Notable Institutions and Research Groups in the US:

  • Stanford University (e.g., research in neural-symbolic integration, commonsense reasoning)
  • MIT Computer Science and AI Lab (CSAIL) (e.g., work on explainable AI, knowledge graphs)
  • UC Berkeley (e.g., causal inference, multi-modal representations)
  • Carnegie Mellon University (CMU) (e.g., knowledge graphs, reasoning over structured data)
  • Google DeepMind (e.g., multi-modal AI, causal reasoning)
  • OpenAI (e.g., neural-symbolic integration, large language models, explainability)

 

Key Conferences and Journals:

  • Conferences: NeurIPS, AAAI, IJCAI, ACL, CVPR (for vision and language), EMNLP (for natural language processing)
  • Journals: Journal of Artificial Intelligence Research (JAIR), IEEE Transactions on Knowledge and Data Engineering, AI Journal, Journal of Machine Learning Research (JMLR)

These are just a few key trends, and the landscape is evolving rapidly as AI systems continue to grow in complexity and capability. The integration of structured knowledge with data-driven approaches seems to be a central theme in much of this research.

Next date in near future: 2024 Conference

Vancouver Convention Center

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